Merge pull request #6446 from segmentio/feat/add-dropevent-error-handler

feat(content): add `DropEvent` error handler

Author: forstisabella

src/connections/functions/insert-functions.md

@@ -113,6 +113,7 @@ You can `throw` the following pre-defined error types to indicate that the funct
 - `InvalidEventPayload`
 - `ValidationError`
 - `RetryError`
+- `DropEvent`
 
 The examples show basic uses of these error types.
 
@@ -156,6 +157,14 @@ async function onTrack(event) {
   }
 }
 
+async function onIdentify(event) {
+  if (event.traits.companyName) {
+    // Drop Event | Do NOT forward event to destination
+    throw new DropEvent('Company name is required')
+  }
+  return event;
+}
+
 ```
 If you don't supply a function for an event type, Segment throws an `EventNotSupported` error by default.